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Marshpepper Smartweed

Persicaria hydropiper (Polygonum hydropiper)

Non-Native

Marshpepper Knotweed Locations in North America
Marshpepper Knotweed Locations in Southeast US

USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov, 28 March 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Illustration: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner’s Sons, New York. Vol. 1: 670.

What is Marshpepper Smartweed?

Physical Characteristics

Leaves:

  • Sword-shaped
  • 1.19-6.3 inches long
  • 0.20-0.78 inches wide

Flowers:

  • Many clusters
  • Drooping
  • Green or greenish white with pink at the tips

Fruit:

  • One seeded
  • Does not open to release fruit when ripe
  • Dark brown or blackish in color
  • Dull
  • 0.08-0.13 inches long

Stem:

  • Growing upward
  • Fleshy
  • 0.25-3.25 feet high

Where Does it Grow?

Non-Native

Marshpepper smartweed is non-native to North America, and it should not be promoted. This plant can be found in wet meadows and streams.

Pros and Cons of Marshpepper Smartweed

This plant is not native to North America, but has naturalized in much of the United States. While it is not illegal to possess this plant in Texas, it should not be introduced into new water bodies and should be treated with herbicide when present.

How to Manage This Plant
Plant Glossary

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Photo Credits: The majority of the aquatic plant line drawings are the copyright of the University of Florida Center for Aquatic Plants (Gainsville). They are used with permission.

Aquatic plant photographs were provided by David Bayne, Jim Davis, Kelly Duffie, Billy Higginbotham, Michael Masser, John Clayton, Chetta Owens, Diane Smith, Joe Snow, Don Steinbach, Bridget Robinson Lassiter and Peter Woods.

You may use these photos, so long as you give credit to AquaPlant.

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